• Size of external openings

9-1.1    Every room, other than rooms used predominantly for the storage of goods, shall be provided with natural light and natural ventilation by means of one or more openings in external walls. These openings shall have a combined area of not less than 10% of habitable rooms and 7.5% for other rooms of the floor space of such opening, and the whole of such openings shall be capable of allowing free and uninterrupted passage of air.

9-1.2    Area of openings in case of warehouse, godown, storage places etc. shall not be less than 5% of the floor space unless the space is mechanically ventilated.

• Size of internal openings

Unless the light and ventilation requirements are met by an air well or ventilation duct, all internal habitable rooms must have openings in internal air wells in addition to door openings not less than 7.5% of the floor area of such room. Access of maintenance of shaft is provided at level for where the shaft is commenced.

• Internal Air Wells

9-3.3    Habitable rooms may receive daylight and natural ventilation from internal air wells which shall conform to the following minimum sizes:-

• For buildings up to 2 storey. 50Sq.ft. (4.6Sq.m) with minimum width of well 5ft. (1.5m).
• For buildings with than 3 to 5 storey, 100Sq. ft. (9.3Sq.m) with minimum      width of well 8ft. (2.44m)

9-3.1.3    For buildings higher than 5 stories, 100Sq.ft. (9.3Sq. m) plus 10Sq.ft. (0.93Sq.m) for each additional floor over 5 story’s and minimum width of well 10ft. (3.0m).

• Where only kitchens, W.C.’s and bathrooms receive daylight and   ventilation from air-wells, their size shall conform with the following as minimum:-
• For buildings up to 2 storey, 25Sq.ft (2.3Sq.m) with minimum width of well 3ft. (0.9m).

10-3.2.2 For buildings with 3 to 5 storey, 50 Sq. ft.(4.6 Sq.m) with minimum  width of well 5ft. (1.5m).

• For buildings higher than 5 story’s, 50 Sq. ft. (4.64 Sq. m) plus 5 Sq.ft. (0.46 Sq.m) for each additional floor with minimum width of well 5ft. (1.5m).
• Access for maintenance of each such shaft shall be provided at lowest level of the shaft.
• Permanent Openings in Kitchen

Every Kitchen shall have openings for permanent ventilation into the external air space not less than 15% of its floor area.

• Water Closet, Bath Room & Ablution Places.

Every water closet, urinal stall, and both room and ablution area shall be provided with natural lighting and ventilation by means of one or more openings in external walls having a combined area of not less than 2 Esq. (0.2 sq. m) per water closet, urinal or bathroom except where adequate and permanent mechanical ventilation is provided and which discharges into an open space.

9-6.      Garages

Every garage shall be provided with opening of not less than 5% of the floor area for ventilation and incorporated in a wall or in the door.

• Staircases

All Staircases